The invention relates to the field of cosmetic oil bodies or components and concerns an improved method for producing Guerbet alcohols without the use of heavy metal catalysts.
Guerbet alcohols represent primary alcohols which are branched in the 2-position and which are obtained by the condensation of linear fatty alcohols. The products are used predominantly as oil components for the production of cosmetic emulsions. The basic starting point for the production thereof is generally fatty alcohols which in a first step undergo self-condensation under the influence of strong bases and heavy metal compounds such as for example copper or zinc oxide. It is assumed that, under the reaction conditions, the alcohol is firstly dehydrated to form the aldehyde, the latter reacting with itself in an aldol condensation and the condensation product is then hydrated to form the alcohol. An overview in that respect is to be found for example in Angew. Chem. 64, 212 (1952).
There is, however, the disadvantage that the heavy metal catalysts have to be separated off again after the reaction is terminated in order to satisfy statutory requirements and to ensure that they do not cause irritations in the later use. Separation is generally effected by washing with subsequent distillation, in which respect the latter involves not inconsiderable product losses.
Accordingly the object of the present invention is to provide a method of producing Guerbet alcohols which, compared to the state of the art, operates more economically and with reduced environmental pollution. In particular, the invention seeks to avoid the use of heavy metal catalysts and simple distillative purification of the products should be guaranteed without expensive centrifugal washing.